prefix: boolean | Function

key: string

The prefix before class names, this defaults to css. It will also be set as the value of the data-emotion attribute on the style tags that emotion inserts and it's used in the attribute name that marks style elements in renderStylesToString and renderStylesToNodeStream. This is required if using multiple emotion instances in the same app.

container: HTMLElement

A DOM Node that emotion will insert all of it's style tags into, this is useful for inserting styles into iframes.